Effect of Soil Bulk Density on Water Infiltration in Layered Soil

Abstract

The optimal design of various irrigation systems requires knowledge and a deep understanding of various soil properties. Water infiltration in the soil is among the most prominent of these characteristics. Ten laboratory experiments were conducted to study the effect of the bulk density of stratified soils (two-layered soils), Where sandy loam soil, and clay soil were used. Three bulk density values were adopted for each soil, and experiments were conducted in different sequences. New empirical relationships were derived to calculate the cumulative infiltration depth and the depth of the wetting front in terms of time and the basic infiltration rate of the soil. The results revealed a high agreement between the values measured in the laboratory and those estimated from the proposed empirical equations for infiltration and wetting front depths with a coefficient of determination of 0.96 and 0.98, respectively. The results showed that the infiltration and wetting front depths increased with the cumulative infiltration time and the soil bulk density reduction, regardless of the soil location in the upper or lower layer within the stratified soil. It was also found that the infiltration rate was affected by the density of the upper stratum more than its influence by the change in the density of the lower stratum.